freebsd-nq/sys/kern/init_main.c

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/*
* Copyright (c) 1995 Terrence R. Lambert
* All rights reserved.
*
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* Copyright (c) 1982, 1986, 1989, 1991, 1992, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)init_main.c 8.9 (Berkeley) 1/21/94
* $Id: init_main.c,v 1.94 1998/06/07 17:11:32 dfr Exp $
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*/
#include "opt_devfs.h"
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#include <sys/param.h>
#include <sys/file.h>
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#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
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#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/sysent.h>
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#include <sys/reboot.h>
#include <sys/sysproto.h>
#include <sys/vmmeter.h>
#include <sys/unistd.h>
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#include <machine/cpu.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <sys/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <sys/user.h>
#include <sys/copyright.h>
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extern struct linker_set sysinit_set; /* XXX */
extern void __main __P((void));
extern void main __P((void *framep));
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/* Components of the first process -- never freed. */
static struct session session0;
static struct pgrp pgrp0;
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struct proc proc0;
static struct pcred cred0;
static struct filedesc0 filedesc0;
static struct plimit limit0;
static struct vmspace vmspace0;
struct proc *initproc;
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int cmask = CMASK;
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extern struct user *proc0paddr;
struct vnode *rootvp;
int boothowto = 0; /* initialized so that it can be patched */
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struct timeval boottime;
SYSCTL_STRUCT(_kern, KERN_BOOTTIME, boottime,
CTLFLAG_RD, &boottime, timeval, "");
static int shutdowntimeout = 120;
SYSCTL_INT(_kern, OID_AUTO, shutdown_timeout,
CTLFLAG_RW, &shutdowntimeout, 0, "");
/*
* Promiscuous argument pass for start_init()
*
* This is a kludge because we use a return from main() rather than a call
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* to a new routine in locore.s to kick the kernel alive from locore.s.
*/
static void *init_framep;
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#if __GNUC__ >= 2
void __main() {}
#endif
/*
* This ensures that there is at least one entry so that the sysinit_set
* symbol is not undefined. A sybsystem ID of SI_SUB_DUMMY is never
* executed.
*/
SYSINIT(placeholder, SI_SUB_DUMMY,SI_ORDER_ANY, NULL, NULL)
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/*
* System startup; initialize the world, create process 0, mount root
* filesystem, and fork to create init and pagedaemon. Most of the
* hard work is done in the lower-level initialization routines including
* startup(), which does memory initialization and autoconfiguration.
*
* This allows simple addition of new kernel subsystems that require
* boot time initialization. It also allows substitution of subsystem
* (for instance, a scheduler, kernel profiler, or VM system) by object
* module. Finally, it allows for optional "kernel threads".
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*/
void
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main(framep)
void *framep;
{
register struct sysinit **sipp; /* system initialization*/
register struct sysinit **xipp; /* interior loop of sort*/
register struct sysinit *save; /* bubble*/
/*
The biggie: Get rid of the UPAGES from the top of the per-process address space. (!) Have each process use the kernel stack and pcb in the kvm space. Since the stacks are at a different address, we cannot copy the stack at fork() and allow the child to return up through the function call tree to return to user mode - create a new execution context and have the new process begin executing from cpu_switch() and go to user mode directly. In theory this should speed up fork a bit. Context switch the tss_esp0 pointer in the common tss. This is a lot simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer to each process's tss since the esp0 pointer is a 32 bit pointer, and the sd_base setting is split into three different bit sections at non-aligned boundaries and requires a lot of twiddling to reset. The 8K of memory at the top of the process space is now empty, and unmapped (and unmappable, it's higher than VM_MAXUSER_ADDRESS). Simplity the pmap code to manage process contexts, we no longer have to double map the UPAGES, this simplifies and should measuably speed up fork(). The following parts came from John Dyson: Set PG_G on the UPAGES that are now in kernel context, and invalidate them when swapping them out. Move the upages object (upobj) from the vmspace to the proc structure. Now that the UPAGES (pcb and kernel stack) are out of user space, make rfork(..RFMEM..) do what was intended by sharing the vmspace entirely via reference counting rather than simply inheriting the mappings.
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* Copy the locore.s frame pointer for proc0, this is forked into
* all other processes.
*/
init_framep = framep;
/*
* Perform a bubble sort of the system initialization objects by
* their subsystem (primary key) and order (secondary key).
*
* Since some things care about execution order, this is the
* operation which ensures continued function.
*/
for( sipp = (struct sysinit **)sysinit_set.ls_items; *sipp; sipp++) {
for( xipp = sipp + 1; *xipp; xipp++) {
if( (*sipp)->subsystem < (*xipp)->subsystem ||
( (*sipp)->subsystem == (*xipp)->subsystem &&
(*sipp)->order < (*xipp)->order))
continue; /* skip*/
save = *sipp;
*sipp = *xipp;
*xipp = save;
}
}
/*
* Traverse the (now) ordered list of system initialization tasks.
* Perform each task, and continue on to the next task.
*
* The last item on the list is expected to be the scheduler,
* which will not return.
*/
for( sipp = (struct sysinit **)sysinit_set.ls_items; *sipp; sipp++) {
if( (*sipp)->subsystem == SI_SUB_DUMMY)
continue; /* skip dummy task(s)*/
switch( (*sipp)->type) {
case SI_TYPE_DEFAULT:
/* no special processing*/
(*((*sipp)->func))( (*sipp)->udata);
break;
case SI_TYPE_KTHREAD:
#if !defined(SMP)
/* kernel thread*/
if (fork1(&proc0, RFMEM|RFFDG|RFPROC))
panic("fork kernel thread");
cpu_set_fork_handler(pfind(proc0.p_retval[0]),
(*sipp)->func, (*sipp)->udata);
break;
#endif
case SI_TYPE_KPROCESS:
if (fork1(&proc0, RFFDG|RFPROC))
panic("fork kernel process");
cpu_set_fork_handler(pfind(proc0.p_retval[0]),
(*sipp)->func, (*sipp)->udata);
break;
default:
panic( "init_main: unrecognized init type");
}
}
panic("Shouldn't get here!");
/* NOTREACHED*/
}
/*
* Start a kernel process. This is called after a fork() call in
* main() in the file kern/init_main.c.
*
* This function is used to start "internal" daemons.
*/
/* ARGSUSED*/
void
kproc_start(udata)
void *udata;
{
struct kproc_desc *kp = udata;
struct proc *p = curproc;
#ifdef DIAGNOSTIC
printf("Start pid=%d <%s>\n",p->p_pid, kp->arg0);
#endif
/* save a global descriptor, if desired*/
if( kp->global_procpp != NULL)
*kp->global_procpp = p;
/* this is a non-swapped system process*/
p->p_flag |= P_INMEM | P_SYSTEM;
/* set up arg0 for 'ps', et al*/
strcpy( p->p_comm, kp->arg0);
/* call the processes' main()...*/
(*kp->func)();
/* NOTREACHED */
panic("kproc_start: %s", kp->arg0);
}
/*
***************************************************************************
****
**** The following SYSINIT's belong elsewhere, but have not yet
**** been moved.
****
***************************************************************************
*/
#ifdef OMIT
/*
* Handled by vfs_mountroot (bad idea) at this time... should be
* done the same as 4.4Lite2.
*/
SYSINIT(swapinit, SI_SUB_SWAP, SI_ORDER_FIRST, swapinit, NULL)
#endif /* OMIT*/
static void print_caddr_t __P((void *data));
static void
print_caddr_t(data)
void *data;
{
printf("%s", (char *)data);
}
SYSINIT(announce, SI_SUB_COPYRIGHT, SI_ORDER_FIRST, print_caddr_t, copyright)
/*
***************************************************************************
****
**** The two following SYSINT's are proc0 specific glue code. I am not
**** convinced that they can not be safely combined, but their order of
**** operation has been maintained as the same as the original init_main.c
**** for right now.
****
**** These probably belong in init_proc.c or kern_proc.c, since they
**** deal with proc0 (the fork template process).
****
***************************************************************************
*/
/* ARGSUSED*/
static void proc0_init __P((void *dummy));
static void
proc0_init(dummy)
void *dummy;
{
register struct proc *p;
register struct filedesc0 *fdp;
register unsigned i;
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/*
* Initialize the current process pointer (curproc) before
* any possible traps/probes to simplify trap processing.
*/
p = &proc0;
curproc = p; /* XXX redundant*/
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/*
* Initialize process and pgrp structures.
*/
procinit();
/*
* Initialize sleep queue hash table
*/
sleepinit();
/*
* additional VM structures
*/
vm_init2();
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/*
* Create process 0 (the swapper).
*/
LIST_INSERT_HEAD(&allproc, p, p_list);
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p->p_pgrp = &pgrp0;
LIST_INSERT_HEAD(PGRPHASH(0), &pgrp0, pg_hash);
LIST_INIT(&pgrp0.pg_members);
LIST_INSERT_HEAD(&pgrp0.pg_members, p, p_pglist);
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pgrp0.pg_session = &session0;
session0.s_count = 1;
session0.s_leader = p;
p->p_sysent = &aout_sysvec;
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p->p_flag = P_INMEM | P_SYSTEM;
p->p_stat = SRUN;
p->p_nice = NZERO;
p->p_rtprio.type = RTP_PRIO_NORMAL;
p->p_rtprio.prio = 0;
/*
* Link for kernel based threads
*/
p->p_peers = 0;
p->p_leader = p;
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bcopy("swapper", p->p_comm, sizeof ("swapper"));
/* Create credentials. */
cred0.p_refcnt = 1;
p->p_cred = &cred0;
p->p_ucred = crget();
p->p_ucred->cr_ngroups = 1; /* group 0 */
/* Create the file descriptor table. */
fdp = &filedesc0;
p->p_fd = &fdp->fd_fd;
fdp->fd_fd.fd_refcnt = 1;
fdp->fd_fd.fd_cmask = cmask;
fdp->fd_fd.fd_ofiles = fdp->fd_dfiles;
fdp->fd_fd.fd_ofileflags = fdp->fd_dfileflags;
fdp->fd_fd.fd_nfiles = NDFILE;
/* Create the limits structures. */
p->p_limit = &limit0;
for (i = 0; i < sizeof(p->p_rlimit)/sizeof(p->p_rlimit[0]); i++)
limit0.pl_rlimit[i].rlim_cur =
limit0.pl_rlimit[i].rlim_max = RLIM_INFINITY;
limit0.pl_rlimit[RLIMIT_NOFILE].rlim_cur =
limit0.pl_rlimit[RLIMIT_NOFILE].rlim_max = maxfiles;
limit0.pl_rlimit[RLIMIT_NPROC].rlim_cur =
limit0.pl_rlimit[RLIMIT_NPROC].rlim_max = maxproc;
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i = ptoa(cnt.v_free_count);
limit0.pl_rlimit[RLIMIT_RSS].rlim_max = i;
limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_max = i;
limit0.pl_rlimit[RLIMIT_MEMLOCK].rlim_cur = i / 3;
limit0.p_cpulimit = RLIM_INFINITY;
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limit0.p_refcnt = 1;
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/* Allocate a prototype map so we have something to fork. */
pmap_pinit0(&vmspace0.vm_pmap);
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p->p_vmspace = &vmspace0;
vmspace0.vm_refcnt = 1;
vm_map_init(&vmspace0.vm_map, round_page(VM_MIN_ADDRESS),
VM level code cleanups. 1) Start using TSM. Struct procs continue to point to upages structure, after being freed. Struct vmspace continues to point to pte object and kva space for kstack. u_map is now superfluous. 2) vm_map's don't need to be reference counted. They always exist either in the kernel or in a vmspace. The vmspaces are managed by reference counts. 3) Remove the "wired" vm_map nonsense. 4) No need to keep a cache of kernel stack kva's. 5) Get rid of strange looking ++var, and change to var++. 6) Change more data structures to use our "zone" allocator. Added struct proc, struct vmspace and struct vnode. This saves a significant amount of kva space and physical memory. Additionally, this enables TSM for the zone managed memory. 7) Keep ioopt disabled for now. 8) Remove the now bogus "single use" map concept. 9) Use generation counts or id's for data structures residing in TSM, where it allows us to avoid unneeded restart overhead during traversals, where blocking might occur. 10) Account better for memory deficits, so the pageout daemon will be able to make enough memory available (experimental.) 11) Fix some vnode locking problems. (From Tor, I think.) 12) Add a check in ufs_lookup, to avoid lots of unneeded calls to bcmp. (experimental.) 13) Significantly shrink, cleanup, and make slightly faster the vm_fault.c code. Use generation counts, get rid of unneded collpase operations, and clean up the cluster code. 14) Make vm_zone more suitable for TSM. This commit is partially as a result of discussions and contributions from other people, including DG, Tor Egge, PHK, and probably others that I have forgotten to attribute (so let me know, if I forgot.) This is not the infamous, final cleanup of the vnode stuff, but a necessary step. Vnode mgmt should be correct, but things might still change, and there is still some missing stuff (like ioopt, and physical backing of non-merged cache files, debugging of layering concepts.)
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trunc_page(VM_MAXUSER_ADDRESS));
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vmspace0.vm_map.pmap = &vmspace0.vm_pmap;
p->p_addr = proc0paddr; /* XXX */
#ifndef __alpha__ /* XXX what is this? */
#define INCOMPAT_LITES2
#ifdef INCOMPAT_LITES2
/*
* proc0 needs to have a coherent frame base in its stack.
*/
cpu_set_init_frame(p, init_framep); /* XXX! */
#endif /* INCOMPAT_LITES2*/
#endif
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/*
* We continue to place resource usage info and signal
* actions in the user struct so they're pageable.
*/
p->p_stats = &p->p_addr->u_stats;
p->p_sigacts = &p->p_addr->u_sigacts;
/*
* Charge root for one process.
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*/
(void)chgproccnt(0, 1);
/*
* Initialize the procfs flags (to 0, of course)
*/
p->p_stops = p->p_stype = p->p_step = 0;
}
SYSINIT(p0init, SI_SUB_INTRINSIC, SI_ORDER_FIRST, proc0_init, NULL)
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/* ARGSUSED*/
static void proc0_post __P((void *dummy));
static void
proc0_post(dummy)
void *dummy;
{
struct timespec ts;
/*
* Now can look at time, having had a chance to verify the time
* from the file system. Reset p->p_runtime as it may have been
* munched in mi_switch() after the time got set. Set
* p->p_switchtime to be consistent with this unmunching.
*/
microtime(&proc0.p_stats->p_start);
proc0.p_runtime = 0;
microuptime(&proc0.p_switchtime);
/*
* Give the ``random'' number generator a thump.
* XXX: Does read_random() contain enough bits to be used here ?
*/
nanotime(&ts);
srandom(ts.tv_sec ^ ts.tv_nsec);
/* Initialize signal state for process 0. */
siginit(&proc0);
}
SYSINIT(p0post, SI_SUB_INTRINSIC_POST, SI_ORDER_FIRST, proc0_post, NULL)
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/*
***************************************************************************
****
**** The following SYSINIT's and glue code should be moved to the
**** respective files on a per subsystem basis.
****
***************************************************************************
*/
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init_main.c subr_autoconf.c: Add support for "interrupt driven configuration hooks". A component of the kernel can register a hook, most likely during auto-configuration, and receive a callback once interrupt services are available. This callback will occur before the root and dump devices are configured, so the configuration task can affect the selection of those two devices or complete any tasks that need to be performed prior to launching init. System boot is posponed so long as a hook is registered. The hook owner is responsible for removing the hook once their task is complete or the system boot can continue. kern_acct.c kern_clock.c kern_exit.c kern_synch.c kern_time.c: Change the interface and implementation for the kernel callout service. The new implemntaion is based on the work of Adam M. Costello and George Varghese, published in a technical report entitled "Redesigning the BSD Callout and Timer Facilities". The interface used in FreeBSD is a little different than the one outlined in the paper. The new function prototypes are: struct callout_handle timeout(void (*func)(void *), void *arg, int ticks); void untimeout(void (*func)(void *), void *arg, struct callout_handle handle); If a client wishes to remove a timeout, it must store the callout_handle returned by timeout and pass it to untimeout. The new implementation gives 0(1) insert and removal of callouts making this interface scale well even for applications that keep 100s of callouts outstanding. See the updated timeout.9 man page for more details.
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/* ARGSUSED */
static void root_conf __P((void *dummy));
static void
root_conf(dummy)
void *dummy;
{
cpu_rootconf();
}
SYSINIT(root_conf, SI_SUB_ROOT_CONF, SI_ORDER_FIRST, root_conf, NULL)
/* ARGSUSED*/
static void xxx_vfs_root_fdtab __P((void *dummy));
static void
xxx_vfs_root_fdtab(dummy)
void *dummy;
{
register struct filedesc0 *fdp = &filedesc0;
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/* Get the vnode for '/'. Set fdp->fd_fd.fd_cdir to reference it. */
if (VFS_ROOT(mountlist.cqh_first, &rootvnode))
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panic("cannot find root vnode");
fdp->fd_fd.fd_cdir = rootvnode;
VREF(fdp->fd_fd.fd_cdir);
VOP_UNLOCK(rootvnode, 0, &proc0);
fdp->fd_fd.fd_rdir = rootvnode;
}
SYSINIT(retrofit, SI_SUB_ROOT_FDTAB, SI_ORDER_FIRST, xxx_vfs_root_fdtab, NULL)
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/*
***************************************************************************
****
**** The following code probably belongs in another file, like
**** kern/init_init.c. It is here for two reasons only:
****
**** 1) This code returns to startup the system; this is
**** abnormal for a kernel thread.
**** 2) This code promiscuously uses init_frame
****
***************************************************************************
*/
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static void kthread_init __P((void *dummy));
SYSINIT_KP(init,SI_SUB_KTHREAD_INIT, SI_ORDER_FIRST, kthread_init, NULL)
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The biggie: Get rid of the UPAGES from the top of the per-process address space. (!) Have each process use the kernel stack and pcb in the kvm space. Since the stacks are at a different address, we cannot copy the stack at fork() and allow the child to return up through the function call tree to return to user mode - create a new execution context and have the new process begin executing from cpu_switch() and go to user mode directly. In theory this should speed up fork a bit. Context switch the tss_esp0 pointer in the common tss. This is a lot simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer to each process's tss since the esp0 pointer is a 32 bit pointer, and the sd_base setting is split into three different bit sections at non-aligned boundaries and requires a lot of twiddling to reset. The 8K of memory at the top of the process space is now empty, and unmapped (and unmappable, it's higher than VM_MAXUSER_ADDRESS). Simplity the pmap code to manage process contexts, we no longer have to double map the UPAGES, this simplifies and should measuably speed up fork(). The following parts came from John Dyson: Set PG_G on the UPAGES that are now in kernel context, and invalidate them when swapping them out. Move the upages object (upobj) from the vmspace to the proc structure. Now that the UPAGES (pcb and kernel stack) are out of user space, make rfork(..RFMEM..) do what was intended by sharing the vmspace entirely via reference counting rather than simply inheriting the mappings.
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extern void prepare_usermode __P((void));
static void start_init __P((struct proc *p));
/* ARGSUSED*/
static void
kthread_init(dummy)
void *dummy;
{
/* Create process 1 (init(8)). */
The biggie: Get rid of the UPAGES from the top of the per-process address space. (!) Have each process use the kernel stack and pcb in the kvm space. Since the stacks are at a different address, we cannot copy the stack at fork() and allow the child to return up through the function call tree to return to user mode - create a new execution context and have the new process begin executing from cpu_switch() and go to user mode directly. In theory this should speed up fork a bit. Context switch the tss_esp0 pointer in the common tss. This is a lot simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer to each process's tss since the esp0 pointer is a 32 bit pointer, and the sd_base setting is split into three different bit sections at non-aligned boundaries and requires a lot of twiddling to reset. The 8K of memory at the top of the process space is now empty, and unmapped (and unmappable, it's higher than VM_MAXUSER_ADDRESS). Simplity the pmap code to manage process contexts, we no longer have to double map the UPAGES, this simplifies and should measuably speed up fork(). The following parts came from John Dyson: Set PG_G on the UPAGES that are now in kernel context, and invalidate them when swapping them out. Move the upages object (upobj) from the vmspace to the proc structure. Now that the UPAGES (pcb and kernel stack) are out of user space, make rfork(..RFMEM..) do what was intended by sharing the vmspace entirely via reference counting rather than simply inheriting the mappings.
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start_init(curproc);
prepare_usermode();
/*
The biggie: Get rid of the UPAGES from the top of the per-process address space. (!) Have each process use the kernel stack and pcb in the kvm space. Since the stacks are at a different address, we cannot copy the stack at fork() and allow the child to return up through the function call tree to return to user mode - create a new execution context and have the new process begin executing from cpu_switch() and go to user mode directly. In theory this should speed up fork a bit. Context switch the tss_esp0 pointer in the common tss. This is a lot simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer to each process's tss since the esp0 pointer is a 32 bit pointer, and the sd_base setting is split into three different bit sections at non-aligned boundaries and requires a lot of twiddling to reset. The 8K of memory at the top of the process space is now empty, and unmapped (and unmappable, it's higher than VM_MAXUSER_ADDRESS). Simplity the pmap code to manage process contexts, we no longer have to double map the UPAGES, this simplifies and should measuably speed up fork(). The following parts came from John Dyson: Set PG_G on the UPAGES that are now in kernel context, and invalidate them when swapping them out. Move the upages object (upobj) from the vmspace to the proc structure. Now that the UPAGES (pcb and kernel stack) are out of user space, make rfork(..RFMEM..) do what was intended by sharing the vmspace entirely via reference counting rather than simply inheriting the mappings.
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* This returns to the fork trampoline, then to user mode.
*/
return;
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}
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/*
* List of paths to try when searching for "init".
*/
static char *initpaths[] = {
"/sbin/init",
"/sbin/oinit",
"/sbin/init.bak",
"/stand/sysinstall",
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NULL,
};
/*
* Start the initial user process; try exec'ing each pathname in "initpaths".
* The program is invoked with one argument containing the boot flags.
*/
static void
The biggie: Get rid of the UPAGES from the top of the per-process address space. (!) Have each process use the kernel stack and pcb in the kvm space. Since the stacks are at a different address, we cannot copy the stack at fork() and allow the child to return up through the function call tree to return to user mode - create a new execution context and have the new process begin executing from cpu_switch() and go to user mode directly. In theory this should speed up fork a bit. Context switch the tss_esp0 pointer in the common tss. This is a lot simpler since than swithching the gdt[GPROC0_SEL].sd.sd_base pointer to each process's tss since the esp0 pointer is a 32 bit pointer, and the sd_base setting is split into three different bit sections at non-aligned boundaries and requires a lot of twiddling to reset. The 8K of memory at the top of the process space is now empty, and unmapped (and unmappable, it's higher than VM_MAXUSER_ADDRESS). Simplity the pmap code to manage process contexts, we no longer have to double map the UPAGES, this simplifies and should measuably speed up fork(). The following parts came from John Dyson: Set PG_G on the UPAGES that are now in kernel context, and invalidate them when swapping them out. Move the upages object (upobj) from the vmspace to the proc structure. Now that the UPAGES (pcb and kernel stack) are out of user space, make rfork(..RFMEM..) do what was intended by sharing the vmspace entirely via reference counting rather than simply inheriting the mappings.
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start_init(p)
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struct proc *p;
{
vm_offset_t addr;
struct execve_args args;
int options, i, error;
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char **pathp, *path, *ucp, **uap, *arg0, *arg1;
initproc = p;
/*
* Need just enough stack to hold the faked-up "execve()" arguments.
*/
addr = trunc_page(VM_MAXUSER_ADDRESS - PAGE_SIZE);
if (vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &addr, PAGE_SIZE, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0) != 0)
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panic("init: couldn't allocate argument space");
p->p_vmspace->vm_maxsaddr = (caddr_t)addr;
p->p_vmspace->vm_ssize = 1;
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for (pathp = &initpaths[0]; (path = *pathp) != NULL; pathp++) {
/*
* Move out the boot flag argument.
*/
options = 0;
ucp = (char *)USRSTACK;
(void)subyte(--ucp, 0); /* trailing zero */
if (boothowto & RB_SINGLE) {
(void)subyte(--ucp, 's');
options = 1;
}
#ifdef notyet
if (boothowto & RB_FASTBOOT) {
(void)subyte(--ucp, 'f');
options = 1;
}
#endif
#ifdef BOOTCDROM
(void)subyte(--ucp, 'C');
options = 1;
#endif
#if defined(DEVFS) && defined(SLICE)
(void)subyte(--ucp, 'd');
options = 1;
#endif
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if (options == 0)
(void)subyte(--ucp, '-');
(void)subyte(--ucp, '-'); /* leading hyphen */
arg1 = ucp;
/*
* Move out the file name (also arg 0).
*/
for (i = strlen(path) + 1; i >= 0; i--)
(void)subyte(--ucp, path[i]);
arg0 = ucp;
/*
* Move out the arg pointers.
*/
uap = (char **)((intptr_t)ucp & ~(NBPW-1));
(void)suword((caddr_t)--uap, (long)0); /* terminator */
(void)suword((caddr_t)--uap, (long)(intptr_t)arg1);
(void)suword((caddr_t)--uap, (long)(intptr_t)arg0);
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/*
* Point at the arguments.
*/
args.fname = arg0;
args.argv = uap;
args.envv = NULL;
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/*
* Now try to exec the program. If can't for any reason
* other than it doesn't exist, complain.
*
* Otherwise return to main() which returns to btext
* which completes the system startup.
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*/
if ((error = execve(p, &args)) == 0)
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return;
if (error != ENOENT)
printf("exec %s: error %d\n", path, error);
}
printf("init: not found\n");
panic("no init");
}